Recently, we constructed a cDNA library in E. coli using mRNAs from RS virus-infected cells. By a process of hybrid selection of viral mRNAs using recombinant cDNA plasmids and subsequent cell-free translation of the selected mRNAs, recombinants encoding the viral nucleocapsid protein, phosproprotein, matrix protein and a nonstructural protein were identified. This kind of analysis failed to identify the viral glycoprotein genes since putative precursors for these proteins were not translated in vitro from viral mRNA(s). By a process of colony hybridization, we have grouped several recombinant plasmids from our cDNA library that represent RS viral genes distinct from those previously identified. Successive Northern blot analysis of mRNA from infected cells and uninfected cells allowed us to identify two classes of recombinants, one hybridizing with an RNA 2200 nucleotides in length and another with an RNA 1000 nucleotides long.